Enough, the cough is a mere nothing; it will not kill me. I shall not die of a cough.
I will make sure he he knows that he has done wrong
Montresor says to Fortunato, "My dear Fortunato, you are luckily met." Obviously this is not the case. Fortunato is not lucky to meet Montresor because this is the point where Montresor's revenge plan to kill Fortunato can start taking action.
When Montresor takes Fortunato down to the catacombs to taste the Amontillado, Fortunato begins to cough and Montresor offers to go back. But Fortunato says that the cough won't kill him and they should keep going. What he doesn't realize is that if they continue on he will walk right into Montresor's trap to kill him.
Montressor states, "I must not only punish, but punish with impunity." By saying this he is hinting that he is not only going to make Fortunato pay for what he has done, but he is going to make sure it will never happen again.
Montresor explains him and Fortunato's walk down the hallways as "walls of piled bones, with the casks ad puncheons intermingling, into the inmost recesses of the catacombs." This helps to set a very eerie, suspensful mood.
Montresor says, "Throwing them aside, I soon uncovered a quantity of building stone and mortar. With these materials and with the aid of my trowel, I began vigorously to wall up the entrance of the niche." when he is in the process of trapping Fortunato in the catacomb. The way he describes what he is doing puts a vivid image in the readers' mind.
In the story, Fortunato is dressed as a joker or clown. You another word for a joker or clown is a fool. This perfectly symbolizes how Fortunato got "fooled" into his own death.